This Worldpay document provides reference material on card validation response codes that can be returned in a cnpAPI response. The table below contains a list of possible response codes returned when requesting a card validation check for:

• CVV2 - is an authentication system established by credit card companies to further efforts toward reducing fraud for internet transactions. The card holder is required to enter the CVV2 number in at transaction time to verify that the card is on hand.

• CVC2 - a three-digit security code that is printed on the back of credit cards. The number appears in reverse italic at the top of the signature panel at the end. This program helps validate that a genuine card is being used during a transaction.

• CID- The CID (card identification) number is a 3- or 4-digit code found on a credit card.

NOTE: AMEX does not return card validation response codes. See the downloadable document with a table for additional instructions, as well as the descriptions for the various responses, as they are not included in the actual response code.